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1929- J. M. HIGH, JR 1,738,370

ACTUATING DEVICE FOR LOUD SPEAKERS Filed Aug. 11, 1926 avwento'c Patented Dec. 3, 1929 PATENT @FFICE 5 AC'IITATING DEVICE FOR LOUD-SPEAKERS ..-'..--App1ication filed Au ust Q11, 1926. Serial ml 128,666.

tPhis invention relatesto actuating devices for;loud'-.speakers of; the type used for operating'loud'speakers and similar. sound reproducing devices. One oftheobjectsiofthis invention is the prfovision of a novel a tuating device for loud speakers which includes as one elementa yshapedzpermanentmagnet composed of tungsten or cobalt steel.

Another object of this invention is the provision of an actuating device for loud speakers of very simple construction, so arranged that the pole pieces, and the rest of the operating parts may be quickly mounted in place by two bolts.

A further object of this invention is the construction of an actuating device for loud speakers having pole pieces with a plurality of projections on each of them between which the coil windings are mounted.

A still further object of this invention is the provision of an actuating device for loud speakers having an air gap displaced somewhat oii the transverse center line of the motor, so that the armature is nearer one set of pole pieces, than it is to the other set.

These and many other objects are successfully secured by means of this invention.

This invention resides substantially in the construction, combination, arrangement and relative location of parts, as will be fully described in the following specification.

Referring to the drawings in which the same reference numerals will be used in the several views to indicate the same or similar parts, Figure 1 is an end View of my novel construction.

Figure 2 is a cross-sectional view taken on the line 22 of Figure 3, looking in the direction of the arrows.

Figure 3 is a side elevational view of my actuating device for loud speakers.

Figure 4 is a vertical cross-sectional view taken on the line 41 of Figure 3 looking in the direction of the arrows.

Figure 5 is a perspective view of the coil windings.

Figure 6 is a perspective View of the armature mounting.

The main objects of this invention are the provision of a novel actuatingdevice for loud .speakers, which is as a commercial" loud speaker actuating device very simple and relatively inexpensive to manufacture. One of the most expensive elements of these devices is the horse-shoe magnet usually found mentjof'ths clampi1 1g",bars and have arranged thepole tips so that the armature in its 'normal position is nearer -one' set of' pole ftips than it .is near the other. I have also provided a novel spring support for the stylusl' I Referring to the drawings 1 represents any suitable form of support .for the actuating device for loud speakers which is clamped thereto by means of the bar2 and pole 3. I The actuating device for loud speakers comprises the V-shaped magnet 4, which preferably is constructed of .cobalt or silicon steel, and which has the two poles'5. Clamped to these poles 5 are the pole pieces 6, each of which has two ,parallel separated tips 7. Clamping bars 8 are provided which are attached to the pole pieces 6 by means of machine screws 8 Y which have rounded tips which serve to sepa rate the two part'coilrwindings as shown in Figures 2 and/1. The clamping bars 8 have threaded bores therein which-are engaged by means .of the two bolts 9, which extend through smooth bores in the pole piecesas is clearly shown'in the drawings. The coil comprises two small solenoids 10, which are connected together in series, and which have the insulation material 12 to cover the point of connection. 20 represents the two leads to these coils." The coils are mounted between the tips .7 as shown in Figure 4 and encircle the armature ll,which is supported in notches in the two part reed, supported on the brackets 13 by means of screws 14. The brackets 13 are attached to the clamping bars 8. Supported by one of the screws 8' is a U- shaped spring member 15, which is attached to the armature by means of the rod 17, and which is secured near its outer end to the rod 18. which is securedby any suitable means to the diaphragm or tympanum of the sound reproducing apparatus. The spring member 15 is made relatively wide to prevent transverse vibration thereof to prevent rattling.

I have found that by varyim the distance between the centers of the rods 17 real 18. the pitch range of the device may be varied to suit any particular conditions. I have also discovered that by mounting the armature nearer one set of the pole tips than it is to the other set, it is possible to get a larger volume of sound reproduction from a given size actuating device for loud speakers due to a minimizing of air gap energy losses attained by the modified flux density. distribution in the air gap when said armature is so mounted in this novel fashion. The length of the air gap may be varied by changing the pressure to the pole pieces by means of the clamping bolts.

It will be seen from the foregoing description that I have provided an actuating device for loud speakers having several advantages as-des'cribed heretofore.

I am aware that many changes in the physical arrangement of the parts will'suggcst themselves'to those skilled in the art, and I do not therefore desire to be limited to the construction in the drawings, but rather to the spirit and scope of my invention, as I define it in the appended claims.

What I desire to secure by United States Letters Patent is:

1. In an actuating device for loud speakers with its armature eccentrically disposed therein the combination of a permanent magnet, pole pieces for said magnet forming an air gap, an armature supported in said air gap with its center line to one side of the center line of the gap and thus placed nearer one set of pole pieces, than the other, and magnet windings surrounding said armature.

2. In an actuating device for loud speakers of the type described the combination of a magnet, pole pieces for said magnet to provide an air gap, means for clamping the pole pieces on said magnet under an adjustable pressure to provide an adjustable air gap, an armature eccentrically disposed in said air gap so as to be nearer one of said pole pieces than the other, means for supporting the armature on said pole clamping means and windings surrounding said armature.

3. In an actuating device for loud speakers of the type described, the combination with a magnet. pole pieces on said magnet, clamp ing bars for securing said pole pieces to the magnet. an armature supported on said clamping bars, windings encircling said armature. and a connecting member attached to said armature.

4. In an actuating device for loud speakers of the type described, the combination with a magnet, having two poles, of two pole pieces, one arranged on each magnet pole and on opposite sides, extending towards each other to provide an air gap, two clamping bars a rranged on the other opposite sides and overlying the adjacent pole piece ends to secure said pole pieces to the magnet poles, means to preserve said-combination of clamping bars and pole pieces as a unitary structure. an armature supported on said clamping bars. windings encircling said armature and a connecting member attached to said armature.

In testimony whereof have hereunto set my hand on this fourth day of August 1).,

JOHN LWIEEKER HIGH, JR. 

